The flightdecks on our a/c are filthy. it's so bad that even a patch that looks clean, when wiped with a sanicom, coats it in black muck. Where you can see the filth it is absolutely disgusting.
The problem is that the cleaners aren't allowed to clean the flightdeck in case they break something or press buttons they shoulden't (!) and the engineers say that they are not cleaners and it's not they're department. It's an endless cycle, maybe a new job role should be created, 'Cleaners with flying experience' or 'Pilot's with cleaning experience'!